Olympic National Park is a United States national park located in the state of Washington, on the Olympic Peninsula. The park has four basic regions: the Pacific coastline, alpine areas, the west side temperate rainforest and the forests of the drier east side.

U.S. President Theodore Roosevelt originally created Mount Olympus National Monument on 2 March 1909. It was designated a national park by President Franklin Roosevelt on June 29, 1938. In 1976, Olympic National Park became an International Biosphere Reserve, and in 1981 it was designated a World Heritage Site. In 1988, Congress designated 95 percent of the park as the Olympic Wilderness.

Prior to the influx of European settlers, Olympic's human population consisted of Native Americans, whose use of the peninsula was thought to have consisted mainly of fishing and hunting. However, recent reviews of the record, coupled with systematic archaeological surveys of the mountains (Olympic and other Northwest ranges) are pointing to much more extensive tribal use of especially the subalpine meadows than seemed formerly to be the case. Most if not all Pacific Northwest indigenous cultures were adversely affected by European diseases (often decimated) and other factors, well before ethnographers, business operations and settlers arrived in the region, so what they saw and recorded was a much-reduced native culture-base. Large numbers of cultural sites are now identified in the Olympic mountains, and important artifacts have been found.

When settlers began to appear, extractive industry in the Pacific Northwest was on the rise, particularly in regards to the harvesting of timber, which began heavily in the late 19th and early 20th centuries. Public dissent against logging began to take hold in the 1920s, when people got their first glimpses of the clear-cut hillsides. This period saw an explosion of people's interest in the outdoors; with the growing use of the automobile, people took to touring previously remote places like the Olympic Peninsula.

The formal record of a proposal for a new national park on the Olympic Peninsula begins with the expeditions of well-known figures Lieutenant Joseph O'Neil and Judge James Wickersham, during the 1890s. These notables met in the Olympic wilderness while exploring, and subsequently combined their political efforts to have the area placed within some protected status. Following unsuccessful efforts in the Washington State Legislature in the early 1900s, President Theodore Roosevelt created Mount Olympus National Monument in 1909, primarily to protect the subalpine calving grounds and summer range of the Roosevelt elk herds native to the Olympics.

Public desire for preservation of some of the area grew until President Franklin D. Roosevelt declared ONP a national park in 1938. Even after ONP was declared a park, though, illegal logging continued in the park, and political battles continue to this day over the incredibly valuable timber contained within its boundaries. Logging continues on the Olympic Peninsula, but not within the park. A book detailing the history of the fight for ONP's timber is Olympic Battleground: The Power Politics of Timber Preservation by Carsten Lien.